In-stent Minimal Lumen Diameter Research Articles

Early- and Long-Term Intravascular Ultrasound and Angiographic Findings After Bioabsorbable Magnesium Stent Implantation in Human Coronary Arteries

This study aimed to evaluate the degradation rate and long-term vascular responses to the absorbable metal stent (AMS). The AMS demonstrated feasibility and safety at 4 months in human coronary arteries. The PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting) was a prospective, multicenter clinical trial of 63 patients with coronary artery disease who underwent AMS implantation. Angiography and intravascular ultrasound (IVUS) were conducted immediately after AMS deployment and at 4 months. Eight patients who did not require repeat revascularization at 4 months underwent late angiographic and IVUS follow-up from 12 to 28 months. The AMS was well-expanded upon deployment without immediate recoil. The major contributors for restenosis as detected by IVUS at 4 months were: decrease of external elastic membrane volume (42%), extra-stent neointima (13%), and intra-stent neointima (45%). From 4 months to late follow-up, paired IVUS analysis demonstrated complete stent degradation with durability of the 4-month IVUS indexes. The neointima was reduced by 3.6 +/- 5.2 mm(3), with an increase in the stent cross sectional area of 0.5 +/- 1.0 mm(2) (p = NS). The median in-stent minimal lumen diameter was increased from 1.87 to 2.17 mm at long-term follow-up. The median angiographic late loss was reduced from 0.62 to 0.40 mm by quantitative coronary angiography from 4 months to late follow-up. Intravascular ultrasound imaging supports the safety profile of AMS with degradation at 4 months and maintains durability of the results without any early or late adverse findings. Slower degradation is warranted to provide sufficient radial force to improve long-term patency rates of the AMS.

Avaliação tardia de endopróteses coronarianas com sirolimus: comparação da tomografia computadorizada por múltiplos detectores com a angiografia quantitativa e o ultra-som intracoronariano

To assess the performance of multidetector computed tomography in determining late clinical outcomes of patients undergoing sirolimus-eluting stent implantation. Thirty patients, successfully submitted to sirolimus-eluting stent implantation for more than six months, were selected to participate in the study. All underwent invasive angiography and intravascular ultrasound following CT angiography using iodinated contrast medium at a dose of 1.5 ml/kg. Mean proximal reference diameter was 3.01 +/- 0.31 mm by tomography and 3.14 +/- 0.31 mm by angiography (p = 0.04). When the left circumflex artery was excluded from the analysis, the difference between both examinations was no longer significant (tomography = 3.01 +/- 0.32 mm; angiography = 3.10 +/- 0.30 mm, p = 0.65). Mean distal reference diameter was 2.86 +/- 0.30 mm by tomography and 2.92 +/- 0.32 by angiography (p = 0.25). Mean in-stent minimal lumen diameter was 2.85 +/- 0.25 mm by tomography and 2.85 +/- 0.29 mm by angiography (p = 0.27). Mean minimal in-stent cross-sectional area was 7.19 +/- 1.47 mm(2) by tomography and 6.90 +/- 1.52 mm(2) by intravascular ultrasound (p = 0.36), but there was only a weak correlation between these measurements (r = 0.33). Computed tomography allows the qualitative assessment of sirolimus-eluting stents, accurate estimate of proximal and distal reference diameters of the target vessel, and in-stent minimal lumen diameter. Its correlation with measurements performed using intravascular ultrasound, however, is less strong.

Intracoronary β-irradiation prevents excessive in-stent neointimal proliferation in de novo lesions of patients with high plasma ACE levels. The BetAce randomized trial

This study evaluated vascular brachytherapy (VBT) as a potent antiproliferative treatment to prevent in-stent restenosis (ISR) after coronary angioplasty of de novo lesions in patients carrying the D allele of the I/D polymorphism of the ACE gene and high ACE plasma levels (>34 U/l). A prospective randomized trial was designed to detect a 30% improvement in the minimal lumen diameter (MLD) of the stenotic artery, as measured by quantitative coronary analysis (QCA), 6 months following VBT at the time of stented angioplasty. All patients were carriers of the D allele of the ACE gene, with plasma ACE levels >34 U/l. Thirty-one patients (33 stenoses) were allocated to stent implantation (control group) and 30 patients (31 stenoses) to VBT and stented angioplasty. After angioplasty, in-stent MLD was similar in the two groups. At 6 months in the control group, in-stent MLD had decreased to 1.74+/-0.8 versus 2.25+/-1.05 mm in the VBT group (P=.04). The mean in-stent diameter was 2.3+/-0.8 mm in the control group versus 2.9+/-1.05 mm after VBT (P=.02), and the restenosis rate was 37.5% versus 17.9%, respectively (P=.08). At 6 months, a higher need for target vessel revascularization (TVR) was observed in the control group: 35.5% versus 13.3% (P=.04). This randomized study confirms that patients with high plasma ACE concentrations are exposed to an increased risk for ISR after coronary stenting. The preventive use of VBT in these patients reduced neointimal formation by 65% such that the MLD at follow-up was increased by 29% compared with the control group.

Oral rapamycin to prevent human coronary stent restenosis: A pilot study

Background Recent human trials with rapamycin-eluting stents have shown very low restenosis rates. However, the high costs of these devices preclude their use in routine angioplasty, especially when considering multiple stenting. We evaluated whether orally administered rapamycin inhibits in-stent neointimal growth in patients with unstable angina. Methods We enrolled 15 patients successfully treated with the implantation of a single stent in a single de novo lesion in native coronary arteries. Correct stent expansion and apposition were corroborated with intravascular ultrasound scanning in all patients. Patients received aspirin, clopidogrel, and atorvastatin for 6 months. Rapamycin was administered in a loading dose of 5 mg, followed by 2 mg/day for 4 weeks. Results The reference diameter was 3.4 ± 0.4 mm, lesion length was 11.2 ± 2 mm, lesion type B1 was 36%, and lesion type B2 was 64%. After the procedure, in-stent minimal lumen diameter and diameter stenosis (DS) were 3.3 ± 0.4 mm and 0.3% ± 7.5%, respectively. At 10 days, plasma levels of rapamycin were 7.95 ± 2.6 ng/mL. At 6 months, angiographic determinations demonstrated an in-stent minimal lumen diameter of 2 ± 1 mm, an in-stent DS of 41.3% ± 28.0%, and an in-stent late loss of 1.4 ± 1.1 mm. Binary restenosis (>50% DS) was present in 6 of 15 patients (40%). Target lesion revascularization (coronary artery bypass grafting) was performed in 2 of 15 patients (13.3%). There were no serious adverse events during the 6-month period of follow-up, but 1 patient had severe heartburn caused by esophagitis, and another patient had herpes zoster at the end of the protocol. Conclusions Oral rapamycin was well tolerated, but did not suppress in-stent neointimal growth in this small group of patients.

The Canadian study of the sirolimus-eluting stent in the treatment of patients with long de novo lesions in small native coronary arteries (C-SIRIUS)

ObjectivesWe assessed the safety and effectiveness of the sirolimus-eluting stent (SES) in treating single de novo long lesions in small native coronary arteries compared to an identical bare metal stent (BMS). BackgroundThe SES was previously demonstrated to reduce restenosis significantly. However, patients with long lesions in small vessels have not been well studied and may define a group at very high risk. MethodsThe Canadian Study of the Sirolimus-Eluting Stent in the Treatment of Patients With Long De Novo Lesions in Small Native Coronary Arteries (C-SIRIUS) was a multicenter, randomized, double-blind trial comparing SES versus identical BMS. The primary end point was in-stent minimal lumen diameter (MLD) at eight months. Secondary end points included angiographic restenosis at 8 months, target lesion revascularization (TLR), and major adverse cardiac events (MACE) at 270 days. ResultsA total of 100 patients were enrolled at eight Canadian sites. The in-stent MLD at eight months was 2.46 ± 0.37 mm in the SES compared with 1.49 ± 0.75 mm in the BMS (a 65% increase, p < 0.001). Angiographic restenosis occurred in 1 of 44 SES patients (2.3%, with no in-stent restenosis) and in 23 of 44 BMS patients (52.3%, p < 0.001). At 270 days, there were two clinically driven TLRs in the SES (4%) and nine in the BMS (18%, p = 0.05). The Kaplan-Meier estimate of freedom from MACE at 270 days was 96.0% for SES patients and 81.7% for BMS patients (p = 0.029). ConclusionsPatients with long lesions in small vessels are at very high risk of restenosis. In these patients, the SES dramatically reduces the risk of restenosis at eight months, translating into an excellent clinical outcome at nine months.

Sustained suppression of neointimal proliferation by sirolimus-eluting stents

Background We have previously reported a virtual absence of neointimal hyperplasia 4 months after implantation of sirolimus-eluting stents. The aim of the present investigation was to determine whether these results are sustained over a period of 1 year. Methods and Results Forty-five patients with de novo coronary disease were successfully treated with the implantation of a single sirolimus-eluting Bx VELOCITY stent in Sao Paulo, Brazil (n=30, 15 fast release [group I, GI] and 15 slow release [GII]) and Rotterdam, The Netherlands (15 slow release, GIII). Angiographic and volumetric intravascular ultrasound (IVUS) follow-up was obtained at 4 and 12 months (GI and GII) and 6 months (GIII). In-stent minimal lumen diameter and percent diameter stenosis remained essentially unchanged in all groups (at 12 months, GI and GII; at 6 months, GIII). Follow-up in-lesion minimal lumen diameter was 2.28 mm (GIII), 2.32 mm (GI), and 2.48 mm (GII). No patient approached the ≥50% diameter stenosis at 1 year by angiograp...

The PARAGON stent study: a randomized trial of a new martensitic nitinol stent versus the Palmaz-Schatz stent for treatment of complex native coronary arterial lesions

A new martensitic nitinol stent with improved flexibility and radiopacity was tested to evaluate whether these differences improve initial or long-term outcome. Patients who underwent percutaneous revascularization of a discrete native coronary lesion were randomly assigned to the new stent (PARAGON, n = 349) or to the first-generation Palmaz-Schatz (PS) stent (n = 339). The primary end point was target vessel failure at 6 months (a composite of cardiac or noncardiac death, any infarction in the distribution of the treated vessel, or clinically indicated target vessel revascularization). Secondary end points were, among others, device and procedural success and angiographic restenosis. Mean age was 62 years; diabetes was present in 21% of patients, prior bypass surgery in 6%, and recent infarction in 22% (p = NS for comparison between the 2 randomized arms). The PARAGON stent group had smaller reference vessels (2.97 vs 3.05 mm, p = 0.05), more prior restenosis (8.0% vs 4.5%, p = 0.07), and a longer average stent length (21.3 vs 19.4 mm, p <0.05). Device success was significantly higher in the PARAGON arm (99.1% vs 94.3%, p <0.05). Death and infarction at 6-month follow-up were infrequent in both groups. There was no significant difference in death (2.0% vs 1.2%, p = 0.546), but a higher rate of infarction for the PARAGON cohort (9.2% vs 4.7%, p = 0.025). Although target vessel failure (20.3% vs 12.4%, p = 0.005) and target lesion revascularization (12.0% vs 5.9%, p = 0.005) were higher in the PARAGON group, there was no significant difference in 6-month follow-up in in-stent minimal lumen diameter or in the rate of binary angiographic restenosis. Both PARAGON and PS stents are safe and associated with infrequent adverse events. The PARAGON stent can be delivered more frequently than the first-generation PS stent. Although there was no significant difference in in-stent minimal lumen diameter or the frequency of angiographic restenosis, clinical restenosis was more frequent in the PARAGON group.